Texture painting turns pink
You missed this little step here ... 


For the type, add image texture.
Point the target to the texture named "untitled" you have created in your image editor.
Change the Mapping Coord from "Generated" to "UV" - Paul Gonet




Additional Notes
 When you are done painting your texture go to the UV/Image editor and press F3 to save the image. Otherwise all of your work will be lost. Saving the blend file will not save the image with it. Please read this link: Why did the texture I painted in texture paint mode disappear?


  Image painting will display in render view mode in Cycles setup, but
  to make  sure the image renders, you need to save the image to
  directory and save the changes you make. Many users forget to do this,
  and assume that saving the file will save the state of the image
  painting, and this is false. In the Image Editor, you can choose 'save
  image' or 'save image as' and iterate changes to new images if you
  want. You can also indicate 'pack into file' from there, as well as
  'pack external data' from the File header. - Craig D Jones